# Draft California 2012 Integrated Report( 303(d) List/305(b) Report)

# Supporting Information

## Regional Board 6 - Lahontan Region

Water Body Name: | Bidwell Creek
Water Body ID: | CAR6413004020020603153934
Water Body Type: | River & Stream

DECISION ID | 21161 | Region 6
Bidwell Creek

Pollutant: | Chloride
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceeds the applicable water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region.. 3. None of 15 samples exceeded the water quality objectives and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 21161, Chloride | Region 6
Bidwell Creek
LOE ID: | 4793
Pollutant: | Chloride
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Cold Freshwater Habitat
Aquatic Life Use: | Fish Spawning
Number of Samples: | 5
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled Bidwell Creek under the Region SWAMP program. Fifteen samples were collected over five years (between 2001 and 2005). There were two to four samples per year. The highest single chloride concentration was 0.94 mg/L. The annual average objective was not exceeded.
Data Reference: | 2007. SWAMP Data for Waters of the Surprise Valley Hydrologic Unit
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | The water quality objective is an annual average of 1.0 mg/L (Lahontan Basin Plan Table 3-7).
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | One station was sampled (Bidwell Creek below Mill Creek near Fort Bidwell).
Temporal Representation: | Fifteen samples (two to four per year) were collected between 2001 and 2005.
Environmental Conditions: | Bidwell Creek is tributary to Upper Alkali Lake, an ephemeral desert playa lake in Surprise Valley, Modoc County. Most of its watershed is within Modoc National Forest. The Mill Creek tributary to Bidwell Creek should not be confused with "Mill Creek (Modoc County)", which is directly tributary to Upper Alkali Lake.
QAPP Information: | The data meet the quality assurance requiremens of the SWAMP QAPP.
QAPP Information Reference(s):
Line of Evidence (LOE) for Decision ID 21161, Chloride | Region 6
Bidwell Creek
LOE ID: | 4794
Pollutant: | Chloride
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 15
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled Bidwell Creek under the Region 6 SWAMP program. Fifteen samples were collected over five years (between 2001 and 2005). There were two to four samples per year. The highest single chloride concentration was 0.94 mg/L. The MCL was not exceeded.
Data Reference: | 2007. SWAMP Data for Waters of the Surprise Valley Hydrologic Unit
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | California Maximum Contaminant Levels apply to ambient surface waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for chloride is 250 mg/L.
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | One station was sampled (Bidwell Creek below Mill Creek near Fort Bidwell).
Temporal Representation: | Fifteen samples (two to four per year) were collected between 2001 and 2005.
Environmental Conditions: | Bidwell Creek is tributary to Upper Alkali Lake, an ephemeral desert playa lake in Surprise Valley, Modoc County. Most of its watershed is within Modoc National Forest.The Mill Creek tributary to Bidwell Creek should not be confused with "Mill Creek (Modoc County)", which is directly tributary to Upper Alkali Lake.
QAPP Information: | Sampling was conducted in accordance with the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID | 21266 | Region 6
Bidwell Creek

Pollutant: | Dissolved oxygen saturation
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. The two available samples do not exceed the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the diel, seasonal and annual variability expected in streamflows and dissolved oxygen concentrations in streams of the Lahontan Region. 3. Neither of two samples exceeded the water quality objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 21266, Dissolved oxygen saturation | Region 6
Bidwell Creek
LOE ID: | 5721
Pollutant: | Dissolved oxygen saturation
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Cold Freshwater Habitat
Aquatic Life Use: | Fish Spawning
Number of Samples: | 2
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled Bidwell Creek under the Region 6 SWAMP program. Two dissolved oxygen samples expressed as percent saturation were collected in October 2004 and July 2005. Percent saturation values were 101 and 105 percent, respectively. The objective was not violated. However, sampling frequency was insufficient to define the normal percent saturation regime or to detect change.
Data Reference: | 2007. SWAMP Data for Waters of the Surprise Valley Hydrologic Unit
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | The Lahontan Basin Plan's regionwide narrative objective for dissolved oxygen provides that percent saturation shall not be depressed more than 10 percent nor shall the minimum dissolved oxygen concentration be less than 80 percent of saturation.
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected at one station, "Bidwell Creek below Mill Creek near Fort Bidwell."
Temporal Representation: | Two measurements of dissolved oxygen as percent saturation were taken in October 2004 and July 2005. This sampling frequency was inadequate to characterize diel, seasonal and annual varations in percent saturation, or to detect whether change due to anthropogenic factors has occurred.
Environmental Conditions: | Bidwell Creek is a tributary to Upper Alkali Lake (an ephemeral desert playa lake in Surprise Valley, Modoc County). Its headwaters, and most of its watershed are in Modoc National Forest. The Mill Creek tributary to Bidwell Creek should not be confused with "Mill Creek (Modoc County)", which is directly tributary to Upper Alkali Lake. The Spawning, Reproduction, and Development beneficial use applies to Bidwell Creek in addition to the Cold Freshwater Habitat use.
QAPP Information: | The data meet quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID | 20614 | Region 6
Bidwell Creek

Pollutant: | Fecal Coliform
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.3 of the Listing Policy. Under section 3.3 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. One out of seven samples exceeds the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and bacteria concentrations in streams of the Lahontan Region. The bacteria objective calls for five samples within a 30 day period. 3. One of seven samples exceeded the water quality objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 20614, Fecal Coliform | Region 6
Bidwell Creek
LOE ID: | 5682
Pollutant: | Fecal Coliform
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 7
Number of Exceedances: | 1
Data and Information Type: | Water column surveys (e.g. fecal coliform)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled fecal coliform bacteria in Bidwell Creek between 2003 and 2005. Six of seven samples were estimated counts; the fecal coliform count in the seventh was 45 colonies per 100 mL, exceeding the 40/100 mL limit.
Data Reference: | 2007. SWAMP Data for Waters of the Surprise Valley Hydrologic Unit
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | The Lahontan Basin Plan's regionwide objective for coliform bacteria states: "Waters shall not contain concentrations of coliform organisms attributable to anthropogenic sources, including human and livestock waste. The fecal coliform concentration during any 30-day period shall not exceed a log mean of 20/100 ml, nor shall more than 10 percent of all samples collected during any 30-day period exceed 40/100 ml. The log mean shall ideally be based on a minimum of not less than five samples collected a evenly spaced as practicable during any 30-day period. However, a log mean concentration exceeding 20/100 ml for any 30-day period shall indicate violation of this objective even if fewer than five samples were collected."
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected at one station, "Bidwell Creek below Mill Creek near Fort Bidwell."
Temporal Representation: | Seven quarterly fecal coliform samples were collected between September 2003 and July 2005.
Environmental Conditions: | Bidwell Creek is a tributary to Upper Alkali Lake (an ephemeral desert playa lake in Surprise Valley, Modoc County). Its headwaters, and most of its watershed are in Modoc National Forest. The Mill Creek tributary to Bidwell Creek should not be confused with "Mill Creek (Modoc County)", which is directly tributary to Upper Alkali Lake.
QAPP Information: | The data meet quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
Line of Evidence (LOE) for Decision ID 20614, Fecal Coliform | Region 6
Bidwell Creek
LOE ID: | 5685
Pollutant: | Fecal Coliform
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Water Contact Recreation
Number of Samples: | 7
Number of Exceedances: | 1
Data and Information Type: | Water column surveys (e.g. fecal coliform)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled fecal coliform bacteria in Bidwell Creek between 2003 and 2005. Six of seven samples were estimated counts; the fecal coliform count in the seventh was 45 colonies per 100 mL, exceeding the 40/100 mL limit.
Data Reference: | 2007. SWAMP Data for Waters of the Surprise Valley Hydrologic Unit
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | The Lahontan Basin Plan's regionwide objective for coliform bacteria states: "Waters shall not contain concentrations of coliform organisms attributable to anthropogenic sources, including human and livestock waste. The fecal coliform concentration during any 30-day period shall not exceed a log mean of 20/100 ml, nor shall more than 10 percent of all samples collected during any 30-day period exceed 40/100 ml. The log mean shall ideally be based on a minimum of not less than five samples collected a evenly spaced as practicable during any 30-day period. However, a log mean concentration exceeding 20/100 ml for any 30-day period shall indicate violation of this objective even if fewer than five samples were collected."
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected at one station, "Bidwell Creek below Mill Creek near Fort Bidwell."
Temporal Representation: | Seven quarterly fecal coliform samples were collected between September 2003 and July 2005.
Environmental Conditions: | Bidwell Creek is a tributary to Upper Alkali Lake (an ephemeral desert playa lake in Surprise Valley, Modoc County). Its headwaters, and most of its watershed are in Modoc National Forest. The Mill Creek tributary to Bidwell Creek should not be confused with "Mill Creek (Modoc County)", which is directly tributary to Upper Alkali Lake.
QAPP Information: | The data meet quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID | 20825 | Region 6
Bidwell Creek

Pollutant: | Nitrate
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. None of 15 samples exceeded the water quality objective and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 20825, Nitrate | Region 6
Bidwell Creek
LOE ID: | 4816
Pollutant: | Nitrate
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 15
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical monitoring (conventional pollutants only)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled this station under the Region 6 SWAMP program. The concentrations of nitrate plus nitrite in 8 of 15 were estimates or below the detection level. The remaining samples ranged from 0.002 to 0.121 mg/L. The MCL for nitrate was not exceeded.
Data Reference: | 2007. SWAMP Data for Waters of the Surprise Valley Hydrologic Unit
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MC for nitrate is 45 mg/L as nitrate, equivalent to 10 mg/L as nitrogen.
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected at one station, Bidwell Creek below Mill Creek near Fort Bidwell.
Temporal Representation: | Fifteen samples were collected over 5 years (between 2001 and 2005),
Environmental Conditions: | Bidwell Creek is tributary to Upper Alkali Lake (an ephemeral desert playa lake in Surprise Valley, Modoc County). Most of the watershed is in Modoc National Forest. The Mill Creek tributary to Bidwell Creek is not the same as "Mill Creek (Modoc County)," which is directly tributary to Upper Alkali Lake.
QAPP Information: | The data meet quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID | 21362 | Region 6
Bidwell Creek

Pollutant: | Nitrate/Nitrite (Nitrite + Nitrate as N)
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. None of 15 samples exceeded the Maximum Contaminant Level. There is no biological information available for assessment of compliance with the narrative objective for biostimulatory substances. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The chemical data used do satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. There are no supplementary biological data for assessment of compliance with the biostimulatory substances objective. 3. None of 15 samples exceeded the MCL and this does not exceed the allowable frequency in Table 3.1 of the Listing Policy. Due to the lack of biological data It is not possible to determine whether the biostimulatory substances objective was exceeded. 3. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 21362, Nitrate/Nitrite (Nitrite + Nitrate as N) | Region 6
Bidwell Creek
LOE ID: | 5828
Pollutant: | Nitrate/Nitrite (Nitrite + Nitrate as N)
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Cold Freshwater Habitat
Aquatic Life Use: | Fish Spawning
Number of Samples: | 15
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled this station under the Region 6 SWAMP program. Eight of 15 sampling results were estimated values or below the detection level. The remaining seven samples ranged from 0.002 to 0.121 mg/L. No data on algae or macrophytes were available for assessment of compliance with the "biostimulatory substances" objective.
Data Reference: | 2007. SWAMP Data for Waters of the Surprise Valley Hydrologic Unit
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | There are no site-specific objectives in the Lahontan Basin Plan for nitrate and/or nitrite in Bidwell Creek. (Monitored nitrate plus nitrite data were used to calculate Total Nitrogen to determine compliance with the site-specific objective for that constituent.) The regionwide narrative objective for biostimulatory substances states: "Waters shall not contain biostimulatory substances in concentrations that promote aquatic growths to the extent that such growths cause nuisance or adversely affect the water for beneficial uses."
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected at one station, Bidwell Creek below Mill Creek near Fort Bidwell.
Temporal Representation: | Fifteen samples were collected over 5 years (between 2001 and 2005), with 2 to 4 samples collected per year.
Environmental Conditions: | Bidwell Creek is tributary to Upper Alkali Lake (an ephemeral desert playa lake in Surprise Valley, Modoc County). Most of the watershed is in Modoc National Forest. The Mill Creek tributary to Bidwell Creek should not be confused with "Mill Creek (Modoc County)", which is directly tributary to Upper Alkali Lake. In addition to the Cold Freshwater Habitat beneficial use, Bidwell Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: | The data meet quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
Line of Evidence (LOE) for Decision ID 21362, Nitrate/Nitrite (Nitrite + Nitrate as N) | Region 6
Bidwell Creek
LOE ID: | 7581
Pollutant: | Nitrate/Nitrite (Nitrite + Nitrate as N)
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 15
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled this station under the Region 6 SWAMP program. Eight of 15 sampling results were estimated values or below the detection level. The remaining seven samples ranged from 0.002 to 0.121 mg/L. The MCL was not exceeded.
Data Reference: | 2007. SWAMP Data for Waters of the Surprise Valley Hydrologic Unit
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for nitrite plus nitrate is 10 mg/L expressed "as N."
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected at one station, Bidwell Creek below Mill Creek near Fort Bidwell.
Temporal Representation: | Fifteen samples were collected over 5 years (between 2001 and 2005), with 2 to 4 samples collected per year.
Environmental Conditions: | Bidwell Creek is tributary to Upper Alkali Lake (an ephemeral desert playa lake in Surprise Valley, Modoc County). Most of the watershed is in Modoc National Forest. The Mill Creek tributary to Bidwell Creek should not be confused with "Mill Creek (Modoc County)", which is directly tributary to Upper Alkali Lake. In addition to the Cold Freshwater Habitat beneficial use, Bidwell Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: | The data meet quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID | 21191 | Region 6
Bidwell Creek

Pollutant: | Nitrite
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceeds the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. None of 15 samples exceeded the water quality objective and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 21191, Nitrite | Region 6
Bidwell Creek
LOE ID: | 5849
Pollutant: | Nitrite
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 15
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical monitoring (conventional pollutants only)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled this station under the Region 6 SWAMP program. The concentrations of nitrate plus nitrite in 8 of 15 were estimates or below the detection level. The remaining samples ranged from 0.002 to 0.121 mg/L. The MCL for nitrite was not exceeded.
Data Reference: | 2007. SWAMP Data for Waters of the Surprise Valley Hydrologic Unit
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | The California Maximum Contaminant Level (MCL) for nitrite is 1 mg/L (as N). The MCL applies to ambient waters under the Chemical Constituents objective in the Lahontan Basin Plan..
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected at one station, Bidwell Creek below Mill Creek near Fort Bidwell.
Temporal Representation: | Fifteen samples were collected over 5 years (between 2001 and 2005),
Environmental Conditions: | Bidwell Creek is tributary to Upper Alkali Lake (an ephemeral desert playa lake in Surprise Valley, Modoc County). Most of the watershed is in Modoc National Forest. The Mill Creek tributary to Bidwell Creek is not the same as "Mill Creek (Modoc County)," which is directly tributary to Upper Alkali Lake.
QAPP Information: | The data meet quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID | 20336 | Region 6
Bidwell Creek

Pollutant: | Oxygen, Dissolved
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. None of 11 samples was below the 1 day minimum dissolved oxygen objective and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 20336, Oxygen, Dissolved | Region 6
Bidwell Creek
LOE ID: | 4814
Pollutant: | Oxygen, Dissolved
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Cold Freshwater Habitat
Aquatic Life Use: | Fish Spawning
Number of Samples: | 11
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The minimum dissolved oxygen concentration in 11 quarterly measurements taken by the U.S. Geological Survey under the Region 6 SWAMP program was 8.6 mg/L. The one day minimum objective was not violated.
Data Reference: | 2007. SWAMP Data for Waters of the Surprise Valley Hydrologic Unit
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | The one day minimum dissolved oxygen objective in Lahontan Basin Plan Table 3-6 is 8 mg/L (Basin Plan Table 3-6).
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected at one station, "Bidwell Creek below Mill Creek near Fort Bidwell."
Temporal Representation: | Eleven dissolved oxygen measurements (two to four per year) were taken between 2001 and 2005. This sampling frequency was inadequate to characterize diel, seasonal and annual varations in dissolved oxygen concentration.
Environmental Conditions: | Bidwell Creek is a tributary to Upper Alkali Lake (an ephemeral desert playa lake in Surprise Valley, Modoc County). Its headwaters, and most of its watershed are in Modoc National Forest. The Mill Creek tributary to Bidwell Creek should not be confused with "Mill Creek (Modoc County)", which is directly tributary to Upper Alkali Lake. The "Spawning, Reproduction, and Development" beneficial use applies to Bidwell Creek in addition to the Cold Freshwater Habitat use.
QAPP Information: | The data meet quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID | 21599 | Region 6
Bidwell Creek

Pollutant: | Phosphate
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. There are biological data available for use with the single phosphate sample to determine whether the "biostimulatory substances" objective was exceeded. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The single sample used does not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. Due to the lack of biological data it is not possible to determine whether the biostimulatory substances objective was exceeded. The single phosphate sample does not meet the minimum sample number requirement of Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 21599, Phosphate | Region 6
Bidwell Creek
LOE ID: | 5851
Pollutant: | Phosphate
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Dissolved
Beneficial Use: | Cold Freshwater Habitat
Aquatic Life Use: | Fish Spawning
Number of Samples: | 1
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled this station under the Region 6 SWAMP program. The concentration of dissolved phosphate in one sample collected on March 24, 2004 was 0.02 mg/L. No data on algae or macrophytes were available to permit assessment of compliance with the objective for biostimulatory substances.
Data Reference: | 2007. SWAMP Data for Waters of the Surprise Valley Hydrologic Unit
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | There is no site-specific objective for phosphate in Bidwell Creek. The Lahontan Basin Plan's narrative objective for Biostimulatory Substances states: "Waters shall not contain biostimulatory substances in concentrations that promote aquatic growths to the extent that such growths cause nuisance or adversely affect the waters for beneficial uses."
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected at one station, Bidwell Creek below Mill Creek near Fort Bidwell.
Temporal Representation: | One sample was collected on March 4, 2004.
Environmental Conditions: | Bidwell Creek is tributary to Upper Alkali Lake (an ephemeral desert playa lake in Surprise Valley, Modoc County). Most of the watershed is in Modoc National Forest. The Mill Creek tributary to Bidwell Creek should not be confused with "Mill Creek (Modoc County)", which is directly tributary to Upper Alkali Lake. In addition to the Cold Freshwater Habitat beneficial use, Bidwell Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: | The data meet quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID | 21600 | Region 6
Bidwell Creek

Pollutant: | Phosphorus
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. No biological information is available to assess whether the phosphorus samples exceed the water quality objective for biostimulatory substances. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1 The data used do not satisfy the data quality requirements of section 6.1.4 of the Policy due to an error in the SWAMP QAPP regarding holding times for total phosphorus samples. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. Since no supplementary biological data are available it cannot be determined whether any the total phosphorus samples exceed the water quality objective for biostimulatory substances. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 21600, Phosphorus | Region 6
Bidwell Creek
LOE ID: | 5850
Pollutant: | Phosphorus
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Total
Beneficial Use: | Cold Freshwater Habitat
Aquatic Life Use: | Fish Spawning
Number of Samples: | 15
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled this station under the Region 6 SWAMP program. Of 15 quarterly samples analyzed for total phosphorus, three were estimates and one was below the detection level. Concentrations of total P in the remaining samples ranged from 0.025 to 0.054 mg/L. No data on algae or macrophytes were available to permit assessment of compliance with the objective for biostimulatory substances.
Data Reference: | 2007. SWAMP Data for Waters of the Surprise Valley Hydrologic Unit
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | There is no site-specific objective for phosphorus in Bidwell Creek. The Lahontan Basin Plan's narrative objective for Biostimulatory Substances states: "Waters shall not contain biostimulatory substances in concentrations that promote aquatic growths to the extent that such growths cause nuisance or adversely affect the waters for beneficial uses."
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected at one station, Bidwell Creek below Mill Creek near Fort Bidwell.
Temporal Representation: | Fifteen quarterly samples were collected over 5 years (between 2001 and 2005), with 2 to 4 samples collected per year.
Environmental Conditions: | Bidwell Creek is tributary to Upper Alkali Lake (an ephemeral desert playa lake in Surprise Valley, Modoc County). Most of the watershed is in Modoc National Forest. The Mill Creek tributary to Bidwell Creek should not be confused with "Mill Creek (Modoc County)", which is directly tributary to Upper Alkali Lake. In addition to the Cold Freshwater Habitat beneficial use, Bidwell Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: | Sampling and analysis were done according to the SWAMP QAPP. However, in July 2009 an error was discovered in the QAPP related to holding times for total phosphorus samples that affects the validity of data for the Lahontan Region The holding time for samples that are not acid-preserved.should be 48 hours rather than 28 days as indicated in the QAPP. "Low level" phosphorus analyses, without acid preservation, are used in the Lahontan Region's SWAMP program. .
QAPP Information Reference(s):

DECISION ID | 20983 | Region 6
Bidwell Creek

Pollutant: | Sediment
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: The Lahontan Basin Plan's narrative water quality objective is an antidegradation based objective that provides that there shall be no increases in suspended sediment concentrations or loads. This pollutant is being considered for placement on the section 303(d) list under section 3.10 of the Listing Policy, which deals with trends in water quality. One line of evidence, based on quarterly sampling, is available in the administrative record to assess this pollutant. It includes eleven suspended sediment concentration values and six suspended sediment load values calculated from instantaneous discharge measurements. Suspended sediment concentrations and loads are dependent on flows and can change rapidly over a short time during storm or snowmelt runoff events. Quarterly samples are insufficient to capture these short term events and therefore are insufficient to define natural background suspended sediment concentrations and loads, or to detect trends. Listing Policy Section 3.10 requires that natural background conditions be established. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. Sampling frequency was insufficient to establish natural background conditions and therefore does not meet the requirements of Listing Policy section 3.10. 4.. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 20983, Sediment | Region 6
Bidwell Creek
LOE ID: | 4820
Pollutant: | Sediment
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Aquatic Life Use: | Fish Spawning
Number of Samples: | 11
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey collected suspended sediment samples at quarterly intervals between 2001 and 2005 under the Region 6 SWAMP program, and calculated sediment loads for samples with concurrent flow data. Suspended sediment concentrations ranged from 1 to 8 mg/L. Flows (instantaneous discharge) ranged from 3.7 to 58 cubic feet per second. Suspended sediment loads ranged from 0.03 to 1.2 tons per day. There is insufficient information available to define the normal sediment loading regime, to assess whether changes have occurred due to controllable factors, or to assess whether impacts on beneficial uses have occurred.
Data Reference: | 2007. SWAMP Data for Waters of the Surprise Valley Hydrologic Unit
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | The regionwide objective in the Lahontan Basin Plan states: "The suspended sediment load and suspended sediment discharge rate of surface waters shall not be altered in such a manner as to cause nuisance or adversely affect the water for beneficial uses."
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected at one station, "Bidwell Creek below Mill Creek near Fort Bidwell."
Temporal Representation: | Eleven suspended sediment samples were collected over 4 years (2- 4 samples/year) between 2001 and 2005). Six load calculations were done over 3 years (1-3 calculations/year between 2003 and 2005).
Environmental Conditions: | Bidwell Creek is a tributary to Upper Alkali Lake (an ephemeral desert playa lake in Surprise Valley, Modoc County). Its headwaters, and most of its watershed are in Modoc National Forest. The Mill Creek tributary to Bidwell Creek should not be confused with "Mill Creek (Modoc County)" which is directly tributary to Upper Alkali Lake. The "Spawning, Reproduction, and Development" beneficial use applies to Bidwell Creek in addition to the Cold Freshwater Habitat use.
QAPP Information: | The data meet quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID | 20337 | Region 6
Bidwell Creek

Pollutant: | Specific Conductance
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. None of the samples exceed the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. None of 15 samples exceeded the Maximum Contaminant Level for Specific Conductance and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 20337, Specific Conductance | Region 6
Bidwell Creek
LOE ID: | 4819
Pollutant: | Specific Conductance
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 15
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey took 15 specific conductance measurements at quarterly intervals between 2001 and 2005. Specific conductance levels ranged from 61 to 89 uS/cm. The objective was not exceeded.
Data Reference: | 2007. SWAMP Data for Waters of the Surprise Valley Hydrologic Unit
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | California Maximum Contaminant Levels (MCLs) apply to ambient waters under the "Chemical Constituents" objective. The MCL for specific conductance is 900 microsiemens per centimeter (uS/cm).
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected at one station, "Bidwell Creek below Mill Creek near Fort Bidwell."
Temporal Representation: | Fifteen measurements of specific conductance were taken ( 2-4 measurements per year) over a five year period (2001 to 2005)..
Environmental Conditions: | Bidwell Creek is a tributary to Upper Alkali Lake (an ephemeral desert playa lake in Surprise Valley, Modoc County). Its headwaters, and most of its watershed are in Modoc National Forest. The Mill Creek tributary to Bidwell Creek should not be confused with "Mill Creek (Modoc County)", which is directly tributary to Upper Alkali Lake.
QAPP Information: | The data meet quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID | 21015 | Region 6
Bidwell Creek

Pollutant: | Temperature, water
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: The Lahontan Basin Plan's narrative temperature objective is an antidegradation-based objective that requires that there be no change in temperature in waters designated for the Cold Freshwater Habitat (COLD) beneficial use. The objective does not include specific numerical limits for protection of the COLD use. Listing Policy Section 3.10 contains directions for assessment based on trends in water quality. These directions include requirements to establish specific baseline conditions and specify the influence of seasonal and interannual effects. One line of evidence is available to support this decision. There are not enough temperature samples to establish baseline conditions (including diel, seasonal, annual and interannual variations in temperature) or to detect declining trends in the temperature regime if such trends exist. Because temperature samples were collected only quarterly, weekly and monthly average data are not available for comparison with guidelines in the scientific literature for the temperature requirements of sensitive aquatic species such as salmonids, as directed in Listing Policy Section 6.1.5.9.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 21015, Temperature, water | Region 6
Bidwell Creek
LOE ID: | 4823
Pollutant: | Temperature, water
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Aquatic Life Use: | Fish Spawning
Number of Samples: | 15
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey took 15 temperature measurements over 5 years (2 to 4 per year between 2001 and 2005.) Temperatures ranged from 3 to 13 degrees Celsius. Sampling frequency was inadequate to characterize the natural temperature regime (including diel, seasonal, and annual variations). Sampling frequency was also inadequate to show whether alterations in temperature that would affect beneficial uses have occurred.
Data Reference: | 2007. SWAMP Data for Waters of the Surprise Valley Hydrologic Unit
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | The applicable portion of the temperature objective in the Lahontan Basin Plan states: "The natural receiving water temperature of all waters shall not be altered unless it can be demonstrated to the satisfaction fo the Regional Board that such an alteration in temperature does not adversely affect the water for beneficial uses. For waters designated WARM, water temperature shall not be altered by more than five degrees Fahrenheit ... above or below the natural temperature. For waters designated COLD, the temperature shall not be altered."
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected at one station, "Bidwell Creek below Mill Creek near Fort Bidwell."
Temporal Representation: | Fifteen samples were collected over 5 years (2 to 4 samples per year between 2001 and 2005). Sampling frequency was inadequate to characterize the natural temperature regime or to detect change.
Environmental Conditions: | Bidwell Creek is a tributary to Upper Alkali Lake (an ephemeral desert playa lake in Surprise Valley, Modoc County). Its headwaters, and most of its watershed are in Modoc National Forest. The Mill Creek tributary to Bidwell Creek should not be confused with "Mill Creek (Modoc County)", which is directly tributary to Upper Alkali Lake. The "Spawning, Reproduction, and Development" beneficial use applies to Bidwell Creek in addition to the Cold Freshwater Habitat use.
QAPP Information: | The data meet quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID | 21202 | Region 6
Bidwell Creek

Pollutant: | Total Kjeldahl Nitrogen (TKN)
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. No biological data are available to evaluate compliance with the objective for biostimulatory substances. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. No biological data are available to evaluate compliance with the objective and the data cannot be assessed using Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 21202, Total Kjeldahl Nitrogen (TKN) | Region 6
Bidwell Creek
LOE ID: | 5826
Pollutant: | Total Kjeldahl Nitrogen (TKN)
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Total
Beneficial Use: | Cold Freshwater Habitat
Aquatic Life Use: | Fish Spawning
Number of Samples: | 14
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled this station under the Region 6 SWAMP program. Two out of 14 sampling results were estimated values. The remaining TKN results ranged form 0.05 to 0.23 mg/L. No data on algae or macrophytes were available for assessment of compliance with the "biostimulatory substances" objective.
Data Reference: | 2007. SWAMP Data for Waters of the Surprise Valley Hydrologic Unit
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | There is no site-specific objective in the Lahontan Basin Plan for Total Kjeldahl Nitrogen (TKN) in Bidwell Creek. (Monitored TKN data were used to calculate Total Nitrogen to determine compliance with the site-specific objective for that constituent.) The regionwide narrative objective for biostimulatory substances states: "Waters shall not contain biostimulatory substances in concentrations that promote aquatic growths to the extent that such growths cause nuisance or adversely affect the water for beneficial uses."
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected at one station, Bidwell Creek below Mill Creek near Fort Bidwell.
Temporal Representation: | Fourteen samples were collected over 5 years (between 2001 and 2005), with 2 to 4 samples collected per year.
Environmental Conditions: | Bidwell Creek is tributary to Upper Alkali Lake (an ephemeral desert playa lake in Surprise Valley, Modoc County). Most of the watershed is in Modoc National Forest. The Mill Creek tributary to Bidwell Creek should not be confused with "Mill Creek (Modoc County)", which is directly tributary to Upper Alkali Lake. In addition to the Cold Freshwater Habitat beneficial use, Bidwell Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: | The data meet quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID | 20754 | Region 6
Bidwell Creek

Pollutant: | Total Nitrogen as N
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under section 3.1 of the Listing Policy. Under section 3.1 a single line of evidence is necessary to assess listing status. One line of evidence is available in the administrative record to assess this pollutant. One of the annual average datapoints exceeds the water quality objective. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. Quarterly samples do not capture the seasonal and annual variability expected in streamflows and constituent concentrations in streams of the Lahontan Region. 3. One of five annual average datapoints exceeded the objective and this does not exceed the allowable frequency listed in Table 3.1 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 20754, Total Nitrogen as N | Region 6
Bidwell Creek
LOE ID: | 4815
Pollutant: | Total Nitrogen as N
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Total
Beneficial Use: | Cold Freshwater Habitat
Aquatic Life Use: | Fish Spawning
Number of Samples: | 5
Number of Exceedances: | 1
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey sampled this station under the Region 6 SWAMP program. Calculated total nitrogen concentrations in 7 individual samples ranged from 0.088 to 0.211 mg/L. Seven out of 14 sampling results were estimated values, leading to 3 estimated annual averages. The annual average objective was exceeded in one out of 5 years.
Data Reference: | 2007. SWAMP Data for Waters of the Surprise Valley Hydrologic Unit
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | The site-specific objective (from Lahontan Basin Plan Table 3-7) is 0.2 mg/L total nitrogen, as an annual average.
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected at one station, Bidwell Creek below Mill Creek near Fort Bidwell.
Temporal Representation: | Fourteen samples were collected over 5 years (between 2001 and 2005), with 2 to 4 samples collected per year. Seven samples (2 to 3 per year) were available for the non-estimated values.
Environmental Conditions: | Bidwell Creek is tributary to Upper Alkali Lake (an ephemeral desert playa lake in Surprise Valley, Modoc County). Most of the watershed is in Modoc National Forest. The Mill Creek tributary to Bidwell Creek should not be confused with "Mill Creek (Modoc County)", which is directly tributary to Upper Alkali Lake. In addition to the Cold Freshwater Habitat beneficial use, Bidwell Creek is designated for the Spawning, Reproduction and Development use.
QAPP Information: | The data meet quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID | 21147 | Region 6
Bidwell Creek

Pollutant: | Turbidity
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: This pollutant is being considered for placement on the section 303(d) list under sections 3.2 and 3.10 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Four lines of evidence are available in the administrative record to assess this pollutant. Separate lines of evidence were prepared to assess data expressed as NTU and NTRU, since the two types of units reflect different optical properties and are not directly comparable. Two of the twelve samples expressed as NTU exceed the Maximum Contaminant Level (MCL) incorporated into the water quality objective for Chemical Constituents. The MCL is expressed as NTU, and the three samples expressed as NTRU cannot be used to determine compliance with the MCL. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used satisfy the data quantity requirements of section 6.1.5 of the Policy. 3. Two of twelve measurements expressed as NTU exceeded the MCL and this does not exceed the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 21147, Turbidity | Region 6
Bidwell Creek
LOE ID: | 4824
Pollutant: | Turbidity
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Aquatic Life Use: | Fish Spawning
Number of Samples: | 12
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical monitoring (conventional pollutants only)
Data Used to Assess Water Quality: | The U.S. Geological Survey took 15 turbidity measurements over 5 years (2 to 4 /year between 2001 and 2005) as part of Region 6's SWAMP program. Turbidity in 11 samples ranged from 1.1 to 7.5 NTU. An additional sample was below the detection level. Sampling frequency was insufficient to characterize the normal turbidity regime or to allow identification of changes in this regime or effects on beneficial uses.
Data Reference: | 2007. SWAMP Data for Waters of the Surprise Valley Hydrologic Unit
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | There are no watershed-specific turbidity objectives for Bidwell Creek in the Lahontan Basin Plan. The regionwide objective states: "Waters shall be free of changes in turbidity that cause nuisance or adversely affect the water for beneficial uses. Increases in turbidity shall not exceed natural levels by more than 10 percent."
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected at one station, "Bidwell Creek below Mill Creek near Fort Bidwell."
Temporal Representation: | Twelve turbidity measurements were taken at quarterly intervals over 4 years (2 to 4 samples per year between 2001 and 2004). This sampling frequency was inadequate to characterize the natural turbidity regime or to determine whether changes that would affect beneficial uses have occurred.
Environmental Conditions: | Bidwell Creek is a tributary to Upper Alkali Lake (an ephemeral desert playa lake in Surprise Valley, Modoc County). Its headwaters, and most of its watershed are in Modoc National Forest. The Mill Creek tributary to Bidwell Creek should not be confused with "Mill Creek (Modoc County)", which is directly tributary to Upper Alkali Lake. The Spawning, Reproduction, and Development beneficial use applies to Bidwell Creek in addition to the Cold Freshwater Habitat use.
QAPP Information: | The data meet quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
Line of Evidence (LOE) for Decision ID 21147, Turbidity | Region 6
Bidwell Creek
LOE ID: | 6109
Pollutant: | Turbidity
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Aquatic Life Use: | Fish Spawning
Number of Samples: | 3
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical monitoring (conventional pollutants only)
Data Used to Assess Water Quality: | The U.S. Geological Survey took three quarterly turbidity measurements expressed as NTRU between October 2004 and July 2005 as part of Region 6's SWAMP program. Two samples were below detection level and the third was 5.1 NTRU. Sampling frequency was insufficient to characterize the normal turbidity regime or to allow identification of changes in this regime or effects on beneficial uses.
Data Reference: | 2007. SWAMP Data for Waters of the Surprise Valley Hydrologic Unit
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | There are no watershed-specific turbidity objectives for Bidwell Creek in the Lahontan Basin Plan. The regionwide objective states: "Waters shall be free of changes in turbidity that cause nuisance or adversely affect the water for beneficial uses. Increases in turbidity shall not exceed natural levels by more than 10 percent."
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected at one station, "Bidwell Creek below Mill Creek near Fort Bidwell."
Temporal Representation: | Three quarterly turbidity measurements expressed as NTRU were taken between October 2004 and July 2005. This sampling frequency was inadequate to characterize the natural turbidity regime or to determine whether changes that would affect beneficial uses have occurred.
Environmental Conditions: | Bidwell Creek is a tributary to Upper Alkali Lake (an ephemeral desert playa lake in Surprise Valley, Modoc County). Its headwaters, and most of its watershed are in Modoc National Forest. The Mill Creek tributary to Bidwell Creek should not be confused with "Mill Creek (Modoc County)", which is directly tributary to Upper Alkali Lake. The "Spawning, Reproduction, and Development" beneficial use applies to Bidwell Creek in addition to the Cold Freshwater Habitat use.
QAPP Information: | The data meet quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
Line of Evidence (LOE) for Decision ID 21147, Turbidity | Region 6
Bidwell Creek
LOE ID: | 6114
Pollutant: | Turbidity
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 3
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey took quarterly turbidity measurements as part of Region 6's SWAMP program. Two of three measurements expressed as NTRU were below the detection level and the third was 5.1 NTRU.
Data Reference: | 2007. SWAMP Data for Waters of the Surprise Valley Hydrologic Unit
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | There are no human health standards or criteria for turbidity expressed as NTRU.
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected at one station, "Bidwell Creek below Mill Creek near Fort Bidwell."
Temporal Representation: | Three turbidity measurements expressed as NTRU were taken at quarterly intervals between October 2004 and July 2005.
Environmental Conditions: | Bidwell Creek is a tributary to Upper Alkali Lake (an ephemeral desert playa lake in Surprise Valley, Modoc County). Its headwaters, and most of its watershed are in Modoc National Forest. The Mill Creek tributary to Bidwell Creek should not be confused with "Mill Creek (Modoc County)", which is directly tributary to Upper Alkali Lake.
QAPP Information: | The data meet quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
Line of Evidence (LOE) for Decision ID 21147, Turbidity | Region 6
Bidwell Creek
LOE ID: | 4825
Pollutant: | Turbidity
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 12
Number of Exceedances: | 2
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey took quarterly turbidity measurements (2 to 4 per year between 2001 and 2004) as part of Region 6's SWAMP program. Turbidity in 11 samples ranged from 1.1 to 7.5 NTU. Two of these samples exceeded the MCL. An additional sample was below the detection level.
Data Reference: | 2007. SWAMP Data for Waters of the Surprise Valley Hydrologic Unit
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | California Maximum Contaminant Levels (MCLs) apply to ambient waters through the "Chemical Constituents" objective. The secondary MCL for turbidity is 5 NTU.
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected at one station, "Bidwell Creek below Mill Creek near Fort Bidwell."
Temporal Representation: | Twelve quarterly turbidity measurements expressed as NTU were taken at quarterly intervals over 4 years (2 to 4 samples per year between 2001 and 2004).
Environmental Conditions: | Bidwell Creek is a tributary to Upper Alkali Lake (an ephemeral desert playa lake in Surprise Valley, Modoc County). Its headwaters, and most of its watershed are in Modoc National Forest. The Mill Creek tributary to Bidwell Creek should not be confused with "Mill Creek (Modoc County)", which is directly tributary to Upper Alkali Lake.
QAPP Information: | The data meet quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID | 21306 | Region 6
Bidwell Creek

Pollutant: | pH
Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | Do Not List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: The Lahontan Basin Plan's narrative pH objective is an antidegradation-based objective that requires that there be no change greater than 0.5 pH units in waters designated for the Cold Freshwater Habitat (COLD) or Warm Freshwater Habitat beneficial uses. Listing Policy Section 3.10 contains directions for assessment based on trends in water quality. These directions include requirements to establish specific baseline conditions and specify the influence of seasonal and interannual effects. Two lines of evidence are available to support this decision. The data meet data quality requirements of the Listing Policy. However, there are not enough pH samples to establish baseline conditions (including diel, seasonal, annual and interannual variations) or to detect changes in the pH regime due to controllable factors, if such trends exist.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 21306, pH | Region 6
Bidwell Creek
LOE ID: | 4818
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 15
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey collected pH data at quarterly intervals between 2001 and 2005 under the Region 6 SWAMP program. The range of pH in 15 field measurements and a single laboratory measurement was 7.1 to 8.5 units. The 6.5 to 8.5 unit limits for pH were not exceeded. There are insufficient data available to characterize normal ambient pH levels and evaluate compliance with the 0.5 unit limit on pH changes.
Data Reference: | 2007. SWAMP Data for Waters of the Surprise Valley Hydrologic Unit
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | The regionwide water quality objective for pH in the Lahontan Basin Plan states: "In fresh waters with designated beneficial uses of COLD or WARM, changes in normal ambient pH levels shall not exceed 0.5 pH units. For all other waters of the region, the pH shall not be depressed below 6.5 nor raised above 8.5 units. The Regional Board recognizes that some waters of the Region may have natural pH levels outside of the 6.5 to 8.5 range. Compliance with the pH objective for these waters will be determined on a case-by-case basis."
Objective/Criterion Reference: | 2007. SWAMP Data for Waters of the Surprise Valley Hydrologic Unit
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected at one station, "Bidwell Creek below Mill Creek near Fort Bidwell."
Temporal Representation: | Fifteen field pH measurements and one laboratory measurement were taken (2-4 measurements per year) over a five year period. Sampling frequency was inadequate to characterize diel, seasonal, and annual variation in pH.
Environmental Conditions: | Bidwell Creek is a tributary to Upper Alkali Lake (an ephemeral desert playa lake in Surprise Valley, Modoc County). Its headwaters, and most of its watershed are in Modoc National Forest. The Mill Creek tributary to Bidwell Creek should not be confused with "Mill Creek (Modoc County)", which is directly tributary to Upper Alkali Lake.
QAPP Information: | The data meet quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
Line of Evidence (LOE) for Decision ID 21306, pH | Region 6
Bidwell Creek
LOE ID: | 4817
Pollutant: | pH
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | None
Beneficial Use: | Cold Freshwater Habitat
Aquatic Life Use: | Fish Spawning
Number of Samples: | 15
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey collected pH data at quarterly intervals between 2001 and 2005 under the Region 6 SWAMP program. The range of pH in 15 field measurements and one laboratory measurement was 7.1 to 8.5 units. The 6.5 to 8.5 unit limits for pH were not exceeded There are insufficient data available to characterize normal ambient pH levels and evaluate compliance with the 0.5 unit limit on pH changes.
Data Reference: | 2007. SWAMP Data for Waters of the Surprise Valley Hydrologic Unit
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | The regionwide water quality objective for pH in the Lahontan Basin Plan states: "In fresh waters with designated beneficial uses of COLD or WARM, changes in normal ambient pH levels shall not exceed 0.5 pH units. For all other waters of the region, the pH shall not be depressed below 6.5 nor raised above 8.5 units. The Regional Board recognizes that some waters of the Region may have natural pH levels outside of the 6.5 to 8.5 range. Compliance with the pH objective for these waters will be determined on a case-by-case basis."
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected at one station, "Bidwell Creek below Mill Creek near Fort Bidwell."
Temporal Representation: | Fifteen field pH measurements and one laboratory measurement were taken ( 2-4 measurements per year) over a five year period. Sampling frequency was inadequate to characterize diel, seasonal, and annual variation in pH.
Environmental Conditions: | Bidwell Creek is a tributary to Upper Alkali Lake (an ephemeral desert playa lake in Surprise Valley, Modoc County). Its headwaters, and most of its watershed are in Modoc National Forest. The Spawning, Reproduction, and Development beneficial use applies to Bidwell Creek in addition to the Cold Freshwater Habitat use. The Mill Creek tributary to Bidwell Creek should not be confused with "Mill Creek (Modoc County)", which is directly tributary to Upper Alkali Lake.
QAPP Information: | The data meet quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):

DECISION ID | 30384 | Region 6
Bidwell Creek

Pollutant: | Total Dissolved Solids
Final Listing Decision: | List on 303(d) list (TMDL required list)
Last Listing Cycle's Final Listing Decision: | List on 303(d) list (TMDL required list)(2010)
Revision Status | Original
Sources: | Source Unknown
Expected TMDL Completion Date: | 2021
Impairment from Pollutant or Pollution: | Pollutant
Regional Board Staff Conclusion: | This pollutant was considered for placement on the section 303(d) list in a previous assessment cycle. No new information was reviewed for this current assessment cycle. Therefore, the previous conclusion remains unchanged, and is as follows: Regional Board Conclusion: This pollutant is being considered for placement on the section 303(d) list under section 3.2 of the Listing Policy. Under section 3.2 a single line of evidence is necessary to assess listing status. Two lines of evidence are available in the administrative record to assess this pollutant. None of the samples exceeds the California Maximum Contaminant Level. Five out of five "annual average" datapoints, based on only 2 to 4 samples per year, exceed the site-specific water quality objective. Although the exceedances are enough to justify listing under Listing Policy's binomial model, Lahontan Water Board staff's recommendation is against listing because the samples used to calculate annual averages do not capture the expected seasonal and annual variability.in flow and constituent concentrations. Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification against placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. 3. Five out of five annual average datapoints (based on only 2-4 samples per year) exceeded the site specific objective and this exceeds the allowable frequency listed in Table 3.2 of the Listing Policy. Listing is not recommended because the samples are not temporally representative. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met. State Board Review and Comments: The April 19, 2010 State Water Board staff report for the 2010 Integrated Report recommended to place this water body on the 303(d) list for total dissolved solids based on the State Water Board staff determination that the data were collected over a broad period of time to meet section 6.1.5.3 of the Listing Policy. The State Water Board recommendation is based on the following: Lahontan Regional Board staff had decided not to list this water body because staff thought it had insufficient information to make a decision to list. However, State Board staff finds there are 5 samples to make a decision and this meets the sample size requirements of Table 3.2 of the Listing Policy. On August 4, 2010 the State Water Board approved the staff recommendation to place this water body-pollutant combination on the 303(d) list. The final language for the recommendation is: Based on the readily available data and information, the weight of evidence indicates that there is sufficient justification for placing this water segment-pollutant combination on the section 303(d) list in the Water Quality Limited Segments category. This conclusion is based on the staff findings that: 1. The data used satisfy the data quality requirements of section 6.1.4 of the Policy. 2. The data used do not satisfy the data quantity requirements of section 6.1.5 of the Policy. 3. Five out of five annual average datapoints (based on only 2-4 samples per year) exceeded the site specific objective and this exceeds the allowable frequency listed in Table 3.2 of the Listing Policy. 4. Pursuant to section 3.11 of the Listing Policy, no additional data and information are available indicating that standards are not met.
Regional Board Staff Decision Recommendation: | No new data were assessed for this assessment cycle. The conclusion reached in the previous cycle remains in same. The Regional Board will update this decision when new data and information become available in a future assessment cycle.

Line of Evidence (LOE) for Decision ID 30384, Total Dissolved Solids | Region 6
Bidwell Creek
LOE ID: | 4821
Pollutant: | Total Dissolved Solids
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Total Dissolved
Beneficial Use: | Cold Freshwater Habitat
Aquatic Life Use: | Fish Spawning
Number of Samples: | 5
Number of Exceedances: | 5
Data and Information Type: | Fixed station physical/chemical (conventional plus toxic pollutants)
Data Used to Assess Water Quality: | The U.S. Geological Survey collected 15 TDS samples over 5 years (2- 4 samples/year between 2001 and 2005) under Region 6's SWAMP program. The range of single value TDS concentrations was 53 to 88 mg/L. Calculated annual averages ranged from 65 to 75 mg/L and exceeded the objective in five out of five years.
Data Reference: | 2007. SWAMP Data for Waters of the Surprise Valley Hydrologic Unit
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | The site-specific objective for total dissolved solids (TDS) in Lahontan Basin Plan Table 3-7 is an annual average of 55 mg/L.
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected at one station, "Bidwell Creek below Mill Creek near Fort Bidwell."
Temporal Representation: | Fifteen samples were collected over 5 years (2 to 4 samples per year between 2001 and 2005). Five annual average calculations were done.
Environmental Conditions: | Bidwell Creek is a tributary to Upper Alkali Lake (an ephemeral desert playa lake in Surprise Valley, Modoc County). Its headwaters, and most of its watershed are in Modoc National Forest. The Mill Creek tributary to Bidwell Creek should not be confused with "Mill Creek (Modoc County)", which is directly tributary to Upper Alkali Lake. The "Spawning, Reproduction, and Development" beneficial use applies to Bidwell Creek in addition to the Cold Freshwater Habitat use. TDS concentrations in the lower reach of Bidwell Creek may be influenced by windblown salts from the surface of the Upper Alkali Lake playa.
QAPP Information: | The data meet quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):
Line of Evidence (LOE) for Decision ID 30384, Total Dissolved Solids | Region 6
Bidwell Creek
LOE ID: | 4822
Pollutant: | Total Dissolved Solids
LOE Subgroup: | Pollutant-Water
Matrix: | Water
Fraction: | Total Dissolved
Beneficial Use: | Municipal & Domestic Supply
Number of Samples: | 15
Number of Exceedances: | 0
Data and Information Type: | Fixed station physical/chemical monitoring (conventional pollutants only)
Data Used to Assess Water Quality: | The U.S. Geological Survey collected 15 TDS samples over 5 years (2- 4 samples/year between 2001 and 2005) under Region 6's SWAMP program. The range of TDS concentrations was 53 to 88 mg/L. The MCL was not exceeded.
Data Reference: | 2007. SWAMP Data for Waters of the Surprise Valley Hydrologic Unit
SWAMP Data: | SWAMP
Water Quality Objective/Criterion: | California Maximum Contaminant Levels (MCLs) apply to ambient waters under the Lahontan Basin Plan's "Chemical Constituents" objective. The MCL for total dissolved solids (TDS) is 500 mg/L.
Objective/Criterion Reference: | Water Quality Control Plan for the Lahontan Region (as amended)
Evaluation Guideline: |
Guideline Reference:
Spatial Representation: | Samples were collected at one station, "Bidwell Creek below Mill Creek near Fort Bidwell."
Temporal Representation: | Fifteen quarterly TDS samples were collected over 5 years (2 to 4 samples per year between 2001 and 2005).
Environmental Conditions: | Bidwell Creek is a tributary to Upper Alkali Lake (an ephemeral desert playa lake in Surprise Valley, Modoc County). Its headwaters, and most of its watershed are in Modoc National Forest. The Mill Creek tributary to Bidwell Creek should not be confused with "Mill Creek (Modoc County)", which is directly tributary to Upper Alkali Lake. TDS concentrations in the lower reach of Bidwell Creek may be influenced by windblown salts from the surface of the Upper Alkali Lake playa.
QAPP Information: | The data meet quality assurance requirements of the SWAMP QAPP.
QAPP Information Reference(s):